Science behind cravings of junk food and healthy eating

This article explains scientific facts which explain why we crave more for junk unhealthy foods and choose them over healthy foods. Junk foods carry taste and sensations and thus play with our psycho-biology which make us choose them over healthy meals.


We all know that junk foods are unhealthy. They rarely carry any nutritional value with them and are just packed with lots of calories and high sugar content. On the other hand, healthy food stuffs carry sufficient amount of calories and reward us with all the essential nutrition our body requires on daily basis. Even after knowing all these facts, we still make unhealthy choices when it comes to eating. Not once, nor twice, its like an addiction for us and we have made junk foods as major part of our daily diet. Instead of eating the whole nutritious meal, we prefer to quickly binge on any unhealthy snack as it is easily available and time saving. Many studies have been done regarding this matter and there is science behind choices we make.

Our craving of junk food

According to science, there are two factors which increase our cravings towards junk foods. First is the sensation which is created when we eat junk food. Sensations are very essential and make us choose certain foods over others. Junk foods taste good, smell good as well as feel good in mouth. Healthy foods might not create these kinds of sensations. Manufacturers take complete care of all these essential factors. They add bright colors to the products. They add the agents which gives nice smell to it as well as take care that the food stuff feels good when it is in mouth. For example, companies which manufacture chips take care that their chips have perfect level of crunch in them. When we prepare food in home, we take care of its nutritional value instead of color or sensations felt in the mouth. This is the reason our mind craves for tasty junk foods instead of healthy ones. Second factor is manufacturers keep a perfect combination of salt, sugar and fat in their products. This combination itself is what makes us eat them in more and more amount and on regular basis. Whereas foods we prepare in kitchen do not have that perfect combination. We try to prepare it as nutritious as possible rather than adding our recipes with high amounts of sugar, salt or fat content.

Salivary response excites brain

More saliva excreted means the foods which we are eating will cover or travel more area in our mouth. Even our taste buds will get drenched by it. Sauces, butter, dressings, ice creams, chocolates, ghee all promote excess salivary response. Taste buds will be able to lather up quickly and we experience joy of eating. While eating vegetables or fruits, this type of response is not created. Thus, we feel that junk foods are tasty as emulsified foods cause salivary response. They excite our brain and taste good whereas healthy foods do not excite our brain and thus we do not enjoy them as much as we enjoy eating junk foods.

Vanishing calorie density

Foods which melt in our mouth quickly are over eaten by us. We just do not know how much have we consumed and we always end up eating more. These foods send a signal to brain that we have not eaten enough. Though we are packing in lots of calories, we still feel that we have eaten very less. This itself is known as vanishing calorie density. When food melts quickly, brain feels that there are no calories in it and thus we can keep eating it forever without getting signals of being satiated.

Junk foods are dense in calories

Junk foods carry large amount of calories. Since most of them are deep fried and contain lots of added sugar and other sweeteners, even small portion sizes can supply us with abundant amount of calories. A burger may provide us with same amount of calories a meal would do. The only difference is meal will satisfy our hunger cravings for next 3-4 hours, but burger will make us hungry in next 30 minutes to 1 hour itself. Thus, junk foods are said to be dense in calories. Receptors in mouth and stomach will send signals to brain regarding the nutrition present in food that we are eating and how filling it is for our body. We can eat large amount of junk food in small time and keep eating it until our brain sends a signal that we are full. As compared to a healthy meal, junk food will take longer time to make us feel full and within that duration we will end up eating more.

Junk foods avoid sensory specific response

We cannot eat same food again and again every day cause we tend to lose interest in it. If same type of taste is over experienced then it leads to decrease in sensitivity of that specific sensor. This decrease can take place in very small amount of time. This is the reason that our meal contains variety of food stuffs and not just single one. Our brain very quickly gets tired if same food is eaten for quite some time. Junk foods however do not dull our sensory response. Our brain never gets tired of eating them. Manufacturers avoid this sensory specific response in them. We can eat them in large amounts and still not feel tired. We can continue eating them and sometimes repeat them cause we find their taste and sensation very interesting.

Combination of various sensations

In junk foods we can find multiple sensations experienced by single food. Outer layer may be crunchy or crispy. Inside it may be soft or leathery in consistency. This kind of contrast present excites our brain and taste buds. Pizza, burgers, caramelized products are all therefore very sought after products in different eateries. This is the reason that home cooked healthy foods seem to be bland in front of junk foods which carry combination of different sensations.


When we eat any food, we register it in our memory. Its taste, color, sensations in our mouth and how much pleasure or relaxation it triggered in us, everything gets recorded. Next time when we come across it, read about it, look at it picture or hear about it, our memory about it just re-emerges. We will get back all the sensations we experienced in the past when we consumed it. Salivation takes place and cravings get large enough. This psycho-biology of junk food itself will make us to eat them again and again.

Science behind healthy eating

A transition is essential from eating junk foods to healthy eating. This transition can be quick and abrupt or else can be gradual. Whatever the case may be, one thing is noticed in all the research that is done is that addiction towards junk food decreases if we slow down or stop consuming it. Less we consume it, less cravings develops. If we eat unhealthy junk food on daily basis and then one day if we do not eat it, we get the cravings for it. In the same way, if we follow a healthy nutritious diet and one day if we skip it to eat unhealthy junk food then we will feel guilty for doing it and junk food will seem to us as toxin rather than luring us. Less and less craving period is also known as "gene reprogramming".

Brain needs variety

Brain gets fed up if same food is provided to eat again and again and this as mentioned earlier takes place within minutes. Create interesting sensations in the recipes like maintaining crunch as well as making it a little creamy. Healthy eating can be made comfortable by adding variety to daily meals and altering it with different types of spices and flavors. Bland food never creates novel sensation and thus brain craves for junk foods. To avoid this, work on recipes to make them interesting so that they can create different sensations.

Buying healthy will decrease cravings

If we do not buy junk foods, we will not be able to eat them and thus can save ourselves from unhealthy eating. These junk foods are very powerful and mere memories can cause craving in us. Thus, we need to stop thinking about them. Buy healthy and eat healthy should be the rule that should be followed.

Stress is the main culprit

Stress and anxiety make us to eat unhealthy junk foods cause these foods tend to calm us and relax us. It acts like coping mechanisms. Stress induces release of opiates and neuropeptide Y. These chemicals are known to trigger mechanisms in our body. These mechanisms are very alike to the cravings we experience for junk foods rich in sugar and fat. Thus, stress leads us to eat junk foods. To overcome addiction, overcoming or dealing with stress is essential and this can be done by breathing exercises, yoga, mediation etc.


To live healthy, we need to make healthy choices when it comes to eating. To get rid of junk foods and eat healthy, we need to understand the science behind both of them. Science itself will help us understand that why do we eat unhealthy junk foods when we have so much of healthy food around us. Every single fact and every single detail will help us to understand that why poor eating habits are so complex. Eating healthy will help us to live healthy.

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Author: Umesh06 Jun 2017 Member Level: Diamond   Points : 5

Persons who are addicted to junk foods have great difficulty in getting rid of this tempting addiction and instead go for healthy foods. Even after understanding the science behind these harmful foods one requires a strong will power to change their life style.

Healthy food can also be made tasty with suitable flavours which are from unharmful substances like indian spices viz. Asafoetida, Mango powder, Garam masala, Nutmeg, Cumin powder, Cardamom, black pepper and many others. These can be used in the food in different ways and proportions resulting in different tastes.

So when we have plenty of tasteful options why go for a few Chinese or Italian spices.

Another thing is minimum use of oils in food makes it healthy. Replacing refined flour with coarse one does a great magic of increasing its value from health point of view.

Avoiding fried items and going for flavoured steamed items is also a great step forward.

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